A syringe includes a gasket, a barrel, and a plunger. The plunger includes a helical rib provided at a head portion, and the gasket includes a threaded engagement portion configured to threadedly engaged with the helical rib, a plunger-retaining annular rib, and an accommodation portion for accommodating a part of the plunger at which the helical rib is formed. The annular rib includes a rib absent portion for guiding, to the accommodation portion, the helical rib reaching the annular rib. The gasket further includes an intermediate annular rib provided at a part on a proximal side of the retaining annular rib and a part defined on a side of the distal end of the helical projection, between a distal side annular rib and a proximal side annular rib.